Abstract

A systematic investigation has been carried out on effect of Cr-dopingo structural,magneto-resistance, magnetic and thermoelectric power properties of La0.65Ca0.35Mn1�xCrxO3 compounds. Samples were prepared using conventional solid statereaction method.The XRD analysis using Rietveld refinement revealst hatthe sample are single phased.Temperature dependent electrical resistivity measurements show the existence of the expected metal–insulator transition(TMI) which is followed by a small humpat temperature slower than TMI. With the application of magnetic field, resistivity of all the samples is found
to decreaseand TMI is observed to shift towards higher temperature.This is attributed to induced magnetic ordering of the localizedt2g spins and increased electrontransfer integral between Mn3þ/Mn4þ via oxygen by the application of magnetic field. MR%is observed to increase withthe in-creasing Crconcentration.Magnetic studies show that the Curie temperature, TC and magneticmoment decreases withCr-content which is consistent with thee lectrical studies.Electrical resistivity and
thermoelectric power data have been analyzed using the oretical models and both suggest that the small polaron hopping(SPH)model is operative in the high temperature insulatin gregion for the entire series of samples.